The major hypothesis guiding this study is that intraoperative near-infrared (NIR) fluorescence imaging has the potential to improve human cancer surgery. At the present time, cancer surgery is performed "blindly", without the ability to identify un-resected tumor cells, or to avoid critical nerves and vessels via optical guidance. By introducing exogenous NIR fluorophores targeted to either tumor cells or normal cells, sensitive and specific optical contrast is generated. Cancer-specific applications of intraoperative NIR fluorescence imaging include image-guided resection with real-time assessment of surgical margins, image-guided sentinel lymph node mapping, and intraoperative detection of occult metastases in the surgical field. The Pl's laboratory at the Beth Israel Deaconess Medical Center has developed the concept of a low-cost, safe, and easy to use NIR fluorescence imaging system that permits the surgeon to "see" surgical anatomy and NIR fluorescence simultaneously, non-invasively, with high spatial resolution, in real-time, and without moving parts. The specific aims of this study are to improve the performance of this cancer imaging system by optimizing three critical optical sub-systems. In response to PAR 03-157, and in anticipation of future clinical trials with the imaging system, we have formed an academic-industrial partnership with our laboratory and General Electric Corporation (GE). GE is a world leader in biomedical engineering and medical imaging systems, and brings a wealth of experience in sub-system optimization. Together, we will systematically redesign the optical sub-systems for ambient light rejection, respiratory/cardiac gating, and automated zoom and focus. Each modification will be accompanied by small and large animal validation using targeted NIR fluorescence contrast agents and model systems already developed by our laboratory. Taken together, our study leverages the significant resources of academic and industrial partners to bring intraoperative NIR fluorescence cancer imaging one step closer to the clinic.